The present invention relates to a socket for use in testing whether IC packages after fabrication are good or bad. More particularly, the present invention is concerned with a socket for IC package wherein a large number of contacts are arranged in parallel along the sides of a receptable space formed on a base member, the said contacts each having a contact portion for contact with a lead of an IC package received in the receptacle space and also having a spring portion for urging the contact portion inwards to obtain a contact pressure with respect to the lead of the IC package, and the said contact portion is displaced outwards away from the lead of the IC package against the biasing force of the said spring portion by depression of a cover which covers the base member.
Heretofore, as this type of sockets for IC package, there have been known a socket having levers, which is typified by the socket disclosed in Japanese Patent Laid Open No. 4-154065, and a direct-push type socket, which is typified by the socket disclosed in Japanese Patent Laid Open No. 63-307678.
According to such conventional socket using levers, as shown in FIGS. 9(a), 9(b), 9(c), levers 101 are supported vertically pivotably along a row of contacts 100 which are arranged in a large number in parallel, an operating portion 102 is formed on one end side (outside) of each lever 101, while an engaging portion 103 is formed on the opposite end side (inside) of the lever, and the operating portion 102 is forced down by depression of a cover 104, whereby the lever 101 is moved pivotally downward and a contact portion 105 is displaced outward against the biasing force of a spring portion 106.
According to the foregoing conventional, direct-push type socket, as shown in FIG. 10, an operating portion 201 is integrally formed outside each of contacts 200 which are arranged in a large number in parallel, and it is displaced outward by depression of a cover 202, thereby causing a contact portion 203 to be displaced outward against the biasing force of a spring portion 204.
According to the above conventional structures, the contact portions 105 (203) of the many contacts 100 (200) are displaced outward simultaneously by depression of the cover 104 (202), whereby the mounting and removal of an IC package P can be done in an unloaded condition. However, when the contact pressure of the contact portions 105 (203) against leads P2, the operating load and operation life in the depression of the cover 104 (202), and a sure holding performance for the IC package P, are studied in detail with respect to their technical contents, there still remain the following problems to be solved.
In the socket shown in FIGS. 9(a), 9(b), 9(c), since the spring portion 106 of each contact 100 is of such a shape as illustrated in the same figure and a fulcrum 107 of the lever 101 is a fixed point and the distance from the contact portion 105 is short, the contact portion 105 moves obliquely upward and substantially linearly toward the outside, as indicated by arrow Y1 in (b) of the same figure. In other words, the force for holding the IC package P acts in the direction indicated by arrow Y2 in (c) of the same figure, and thus it is somewhat uncertain whether it will be possible to hold the IC package P firmly.
In the socket shown in FIG. 10, since the contact portion 203 is displaced in the horizontal direction, the force for holding the IC package P acts in the direction of arrow Z in the same figure, so that there occurs poor contact caused by deformation or lateral displacement of the leads P2 of the IC package.